Processors typically receive power to operate when included in a system. The power may be received directly from one or more batteries, or from a power management integrated circuit or system, or the like. When waking from a reduced power mode, it may take time for power supply voltages to stabilize, or to “ramp up.” For example, a processor may be in a sleep mode in which one or more power supply voltages may not be provided to the processor. When exiting the sleep mode, it may take time for the power supply voltages to reach a sufficient value for the processor to operate correctly.